Machine tool for internal thread cutting - has oscillating spindle to allow cutting edge to adapt to pitch of thread being cut

摘要

The machine tool for cutting internal screw threads has a fixed outer housing with a top cover. The top cover has an eccentric stub shaft which supports a self-aligned bearing for the spindle. The spindle has spherical teeth cut in its upper end which mesh with pinions which in turn mesh with an internally toothed ring. When a bevel wheel is driven, the internally toothed ring drives the spindle so that it rotates about its own axis and at the same time oscillates about the centre of the spherical radius of the teeth. This compound motion enables the cutting tool fitted to the spindle to assume the correct angle to suit the pitch of the thread being cut.